Process for treating impregnated tubular articles



R. G. COKER ETAL April 4, 1967 I ROCESS FOR TREATING IMPREGNATED TUBULAR ARTICLES 3 Sheets-Shed 1 Filed June 19, 1963 INV NTORS RICHAEb C1. 5014??? and SEMHUNT 93% ATTORNEY l JAmEs E. Wm

.INVENTORS 5 Sheets-Sheet 2 .R, G. COKER ETAL PROCESS FOR TREATINQIMPREGNATED TUBULAR ARTICLES Filed June 19, 196.3

April 4, 1967 v I Y RlCHAYZbQ.COKEEanJ g/mes E.WHI$ENHUNT A TTOE/VE Y April 1967 R. G. COKER ETAL 3,312,568

PROCESS FOR TREATING IMPREGNATED TUBULAR ARTICLES I Filed June 19, 1963 5 Sheets-Sheet 5 INVENTORS EmHAQb G. CQKEE and gyms E. WHISENHUNT A7TOENEY United States Patent Ofiice 3,3 12,5 68 Patented Apr. 4, 1967 3,312,568 PROCESS FOR TREATING IMPREGNATED TUBULAR ARTICLES Richard G. Coke: and James E. Whisenhunt, Hartsviile,

S.C., assignors to Sonoco Products Company, Hartsville, 5.0., a corporation of South Carolina Filed June 19, 1963, Ser. No. 289,002 4 Claims. (Cl. 117-1191) This invention relates to pitch impregnated articles and more particuarly to a process for treating pitch impregnated wound fibre tubes.

One type of pitch impregnated fibre pipe in present day use is produced by the process of immersing wound fibre tubes in a bath comprising a hot bituminous composition such as pitch under predetermined perssure conditions. The hot pitch or impregnant thoroughly penetrates the fibre tubes while vaporizing the volatile materials such as water contained within the tubes. This pitch impregating step is generally carried out in a sealed pressure chamber or tank in which the fibre tubes or pipes are positioned preferably in a suitable carrier such as a basket or the like. A-fter impregnation of the tube-s, the tank is opened to permit withdrawal of the tubes from the bath. The pitch impregnated tubes, which are preferably stacked on end in the carrier or basket, are then removed from the pitch bath and raised to an elevated position over the bath to permit the excess pitch to drain or strip fromthe surfaces of the tubes into the bath. At the same time, the coating of pitch on the tube surfaces is permitted to solidify.

As the freshly impregnated tubes taken from the pitch bath are quite hot, currents of air move upwardly along the walls of the elevated tubes picking up heat from the tubes so that the temperature of the air increases progressively as the air rises towards the upper ends of the tubes. As a result of this heated air, the surfaces of the tubes adjacent the upper ends of the tubes are maintained at an elevated temperature preventing the pitch on these tube surfaces from solidifying. The coating of pitch on the upper surfaces of the tubes therefore continues to drain and runs down the tubes resulting in an undesirably thin pitch coating on these surfaces.

In addition, as the air currents flow upwardly along the tubes, a chimney efiiect is created drawing in cooler air adjacent the lower ends of the tubes so that the pitch on the lower tube surfaces cools and solidifies rapidly preventing proper pitch drainage. Consequently, an excessively thick pitch coating forms on the surfaces of the tubes adjacent the lower ends resulting from both failure to drain properly as Well as the accumulation of pitch flowing down the surfaces of the tubes from above; The

tubes after cooling therefore contain a highly undesirable,

non-uniform coating of pitch as a result of this overstripping of the tubes surface portions adjacent One end and the understripping of the tubes surface portions adjacent the other end.

Accordingly, a primary object of this invention is to provide a new and novel process for treating pitch impregnated wound fibre tubes.

Another object of this invention is to provide a new and novel process for treating pitch impregnated wound fibre tubes which permits a pitch coating of uniform thickness to be obtained on the surfaces of the tubes.

Still another object of this invention is to provide a new and novel process for solidifying the pitch coating on pitch impregnated wound fibre pipe which permits the proper stripping of pitch from freshly impregnated pipe and which provides a pitch coating of the desired thickness on the pipe surfaces to avoid pitch waste.

A further object of this invention is to provide a new and novel process for treating wound fibre tubes freshly impregnated with pitch which may be carried out easily and rapidly to quickly solidify pitch on the surfaces of the tubes during draining in a uniform manner, which utilizes apparatus of simple and inexpensive construction and which promotes higher production speeds and lower costs. I

Other objects and advantages of the invention will become apparent from the following description taken in connection with the accompanying drawing.

In general, the objects of this invention and other related objects are accomplished by immersing one or more fibre tubes stacked vertically on end in a suitable carrier in a bath of molten pitch so as to impregnate the tubes with the pitch. After impregnation, the tubes are moved out of the pitch bath to an elevated vertically extending position over the bath to permit excess pitch to drain from the tubes into the bath. A flow of cooling air is directed vertically downward over the upper surfaces of the elevated tubes in opposition to the hot air currents normally rising from the lower extremities of the tubes to quickly chill the pitch coating on the surfaces of the tubes and prevent excessive stripping of pitch from the upper sur-' faces thereby providing a pitch coating on the tubes of substantially uniform predetermined thickness throughout the tubes.

The novel features which are believed to be characteristic of the invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and method of operation may be best understood by reference to the following description taken in conjunction with the accompanying drawings in which:

FIGURE 1 is an elevation view of one form of apparatus for practicing the process of the invention;

FIGURE 2 is a plan view partially in section taken substantially along the line 2-2 of FIGURE 1 in the direction of the arrows;

FIGURE 3 is a view similar to FIGURE 2 illustrating the parts of the apparatus in another position;

FIGURE 4 is a sectional view taken substantially along line 44 of FIGURE 2 in the direction of the arrows;

FIGURE 5 is a sectional view taken substantially along line 55 of FIGURE 3 in the direction of the arrows; and

FIGURE 6 is an enlarged sectional view taken substantially along line 66 of FIGURE 3 in the direction of the arrows.

Referring now to the drawings and to FIGURE 1 in particular, the process of the invention is employed to treat one or more fibre tubes 11 which have been impregnated with a bituminous composition such as coal tar pitch or the like. Preferably, a plurality of pitch impregnated fibre tubes are treated in accordance with the invention and the tubes to be treated are stacked on end ina vertically extending position within a suitable carrier such as a basket 12 or the like having wall openings for free passage of pitch therethrough.

In order to impregnate the tubes 11, the basket 12 loaded with tubes and suspended by means of a chain 13 from a hoist 14 associated with a rail 16, is arranged to be positioned within a pressure chamber or tank 17 containing a bath of molten pitch. The tank 17, supported on a floor 18, is arranged to be closed by a closure member or cover 19 to permit impregnation of the tubes in the basket under pressure and vacuum conditions.

A tank 21 suitably supported on the floor 1 8 is also provided. The tank 21 contains a bath of cooling water in which the basket 12 containing the tubes 11 may be immersed for completely cooling or chilling the impregnated tubes 11 after they have been permit-tedto drain or strip off excess pitch in an elevated position over the tank 17 as shown in FIGURE 1.

As specifically illustrative of the invention, a hood or enclosure 23 preferably supported on the floor 1 8 is provided for enclosing the basket '12 containing the pitch impregnated tubes 11 in the elevated position shown in FIG- URE 1. As shown in FIGURES 2, 3, the hood 23 contains side walls 24-27 and a top wall 28.

In order to permit the elevated basket 12 containing tubes 11 to move between the two suspended positions over tanks 17, 21 as shown in FIGURE 1, the enclosure side wall 26 is provided with doors 31, 32 both of which extend from the floor 18 to the enclosure top wall 28. In addition, the enclosure top wall '28 is provided with a slot 7 33 for accommodating the chain 13. The slot 33 is arranged to be closed by a sliding door 34 movable between the open position shown in FIGURE 3 and the closed position shown in FIGURE 2 by means of an actuator 36.

-As shown in FIGURE 6, the sliding door or panel 34 is provided with side rollers 37 along each side edge which move guidably in a U-shaped track designated generally by the numeral 38 and supported on the enclosure top wall 28 as the door 34 moves between the open and closed position. In the closed position of the door as shown in FIG- URE 2, a portion 33a of the slot 33 remains open to receive the chain 13 carrying the basket 12.

In order to solidify the pitch on the impregnated tubes 11 in accordance with the process of the invention, an air chamber 41 is suitably secured within the enclosure 23 to the underside of the enclosure top wall 28 as shown best in FIGURES 4, 5. The air chamber 41 is preferably circular in horizontal cross-section having a side wall 42 and an inwardly directed bottom end flange 43 defining a central opening 44 for receiving the upper end portions of the tubes 11 in the basket 1 2. The cylindrical chamber 41 is split diametrically as indicated at 46, 47 and is hinged to form pivotally movable segments 42a, 42b. Chamber segments 42a, 42b are movable by means of suitably supported actuators 48 between the closed circular position of FIGURE 2 to the open position of FIG- URE 3 to permit the chain 13 and the upper end portions of the tubes 11 in the basket 12 to move within the cham- 'ber 41.

As shown best in FIGURE 2, an air duct 51 is provided which extends through the enclosure side wall 27 and communicates tangentially with the cylindrical chamber 41. Air moving means such as a fan 52 driven by a motor 53 is positioned within the duct 51 for circulating air in the direction of the arrows I into the chamber 41. The incoming flow of air thus introduced into chamber 41 impinges on the arcuate side wall of the chamber and circulates in a circular pattern as shown by the arrows H of FIGURE 2. A second duct 54 is also provided which extends through the enclosure side wall 27 preferably at an intermediate position between the top and bottom of the enclosure. Duct 54 contains a fan 56 for moving air in the direction of the arrows 'P'exteriorly of the enclosure 23.

In the practice of the novel process of the invention, a

plurality of fibre tubes 11 are positioned in the basket 12 and the loaded basket 12 is suspended from the chain 13 as shown in FIGURE 1. The enclosure doors 31, 32 are moved to the open position of FIGURE 3 and the sliding door 34 in the enclosure top wall 28 is moved by means of the actuator 36 to the retracted position of FIG- URE 3 to open up the slot 33. The chamber wall segments 42a, 42b are moved by means of the actuators 48 to the open position of FIGURE 3 to accommodate the chain 13 and basket 12. The loaded basket 12 is then carried by the hoist 14 into the position of FIGURE 1 over the impregnating tank 17 within the enclosure 23 with the basket moving between the enclosure doors 31, 32 and the chain 13 traveling through the open slot '33;

After the basket 12 occupies the position of FIGURE 1 over the tank 17, the sliding door 34 and enclosure doors 31,32 may be moved into the closed position of FIGURE 2 to substantially seal up the enclosure with the exception of the slot portion 33a through which the chain 13 ex- 4 tends. The chamber wall segments 42a, 42b are also moved into the closed circular position of FIGURE 2.

The impregnation of the tubes 11 with a bituminous composition such as pitch is carried out in the well-known manner by positioning the loaded basket 12 within the tank 17 which is filled with hot pitch. To accomplish this step, the basket 12 is positioned in the tank 17 and the chain 13 is released from the basket. The tank closure 19 is then moved from the open position of FIGURE 1 into a tank closing position.

After impregnation of the tubes 11, the tank cover 19 is moved to the open position of FIGURE 1 and the basket 12 loaded with hot pitch impregnated tubes with molten pitch clinging to the tube surfaces is elevated to the position of FIGURE 1 over the tank 17 for drainage. At this time, the upper ends of the impregnated tubes 11 enter the chamber opening 44 as shown best in FIGURE 4 in close fitting relationship with the chamber flange 43.

The fan 52 is then actuated to introduce cooling air into the chamber 41 as shown best in FIGURE 2 so that this cooling air travels in the directions of the arrows I, H in a circular pattern around the chamber wall 42 to subsequently move downwardly in the direction of the arrows T of FIGURE 4. This circular distribution of cooling air permits a substantially uniform flow of air downwardly through all of the tubes at a substantially uniform pressure. At the same time, the fan 56in air duct 54 is actuated to move the cooling air flowing over the tubes 11 out of the enclosure 23.

As a result of the downward flow of cooling air in the direction of the arrows T, a rapid cooling or chilling of the pitch on the tube surfaces adjacent the upper ends of the tubes 11 as well as the remaining surfaces of the tubes is obtained. This circulation of cooling air prevents overstripping by quick chilling of the pitch both from the cooling action of the air itself as well as from its opposition to the hot air currents normally rising from the lower extremities of the tubes which would otherwise inhibit the solidifying of the pitch as explained above. Furthermore, the cooling air flowing downwardly through the tubes 11, uniformly distributed and at a uniform pressure, provides a uniform cooling effect throughout all of the tube surfaces so that proper pitch drainage is obtained and a uniform pitch coating at a selected thickness results.

After solidification of the pitch coating on the tubes 11 is obtained in accordance with the novel process of the invention, the loaded basket 12 is then moved outside of the enclosure 23 by opening the chamber portions 42a, 42b, sliding the door 34 to the open position of FIG- URE 3 to open slot 33 and opening the enclosure doors 31, 32. The basket and impregnated tubes 11 can then be moved to the elevated position of FIGURE 1 over the tank 21 for immersion and thorough chilling in a wa-,

ter bath in tank 21 if desired.

Thus it can be seen that there has been provided with this invention a new and novel process for draining wound fibre pipe impregnated with a bituminous composition such as pitch so as to obtain a uniform coating of a desired thickness on the pipe. The process of the invention eliminates excessive pitch in the coating on the pipe surfaces with an attendant reduction in cost as well as the elimination of the overstripped and understripped areas in the pitch coating which result from present day practices in the drip-draining of hot, freshly impregnated pipe. Furthermore, the novel process of the invention may be carried out in a simple and easy manner using inexpensive readily available apparatus.

While there 'has been described what at present is considered to be the preferred embodiment of the invention, it will be understood by those skilled in the art that various changes and modifications may be made therein without departing from the invention and, therefore, it is the aim of the appended claims to cover all such changes and modifications as fall within the true spirit and scope of the invention.

Having thus described the invention, what is claimed is:

1. A process for treating pitch impregnated wound fibre tubes comprising the steps of, immersing at least one fibre tube in a bath of molten pitch to impregnate said tubes with said pitch, removing said impregnated tube from said bath to an elevated vertically extending position to permit excess pitch to drain from said tube, and directing a flow of cooling air vertically downward through the interior and over the upper surfaces of said elevated tube in opposition to the hot air currents normally rising from the lower extremities of said tube to quickly chill the pitch coating throughout the surfaces of said tube.

2. A process for treating pitch impregnated fibre tubes comprising the steps of, immersing a plurality of fibre tubes in a bath of molten pitch to impregnate said tubes with said pitch, removing said impregnated tubes from said bath to an elevated vertically extending position over said bath to permit excess pitch to drain from said tubes into said bath, directing a flow of cooling air vertically downward through the interior and over the upper surfaces of said elevated tubes in opposition to the hot air currents normally rising from the lower extremities of said tubes, confining the portion of said downwardly directed flow of cooling air exterior of said tube to a horizontal area defined substantially by the upper ends of said tubes to quickly chill the pitch coating throughout the surfaces of said tubes.

3. A process for treating pitch impregnated fibre tubes comprising the steps of, immersing a stack of fibre tubes in a bath of molten pitch to impregnate said tubes with said pitch, removing said impregnated tubes from said bath to an elevated vertically extending position over said bath to permit excess pitch to drain from said tubes into said bath, directing a flow of cooling air vertically downward through the interiors and over the upper surfaces of said elevated tubes in opposition to the hot air currents normally rising from the lower extremities of said tubes, confining the portion of said downwardly directed flow of cooling air exterior of said tube to a horizontal area defined substantially by the upper ends of said tubes, moving said confined flow of cooling air prior to said downward flow in an arcuate path above the upper ends of said tubes to quickly and uniformly chill the pitch coating throughout the surfaces of said tubes.

4. A process for treating pitch impregnated fibre tubes comprising the steps of, immersing a stack of fibre tubes in a bath of molten pitch to impregnate said tubes with said pitch, removing said stack of impregnated tubes from said bath to an elevated vertically extending position over said bath to permit excess pitch to drain from said tubes into said bath, enclosing the upper end portions of said elevated tubes with a chamber substantially circular in horizontal cross-section with said tube end portions in close fitting relationship with said chamber, enclosing said chamber and said elevated tubes in an enclosure, introducing a fiow of cooling air tangentially into said chamber whereby said flow of cooling air flows in an arcuate path defined by the walls of said chamber and is subsequently directed vertically downward through the interiors and over the upper surfaces of said elevated tubes in opposition to the hot air currents normally rising from the lower extremities of said tubes to quickly and uniformly chill the pitch coating throughout the surfaces of said tubes and removing from said enclosure the air introduced into said chamber.

References Cited by the Examiner UNITED STATES PATENTS 2,012,968 9/1935 Miller.

2,096,888 9/1937 Emberg.

2,133,390 9/1938 Kotcher et a1. 1l869 2,287,024 6/1942 Casellini ll858 2,375,113 5/1945 Klammt et a1. 117-1l9.6 X 2,628,173 2/1953 Fair l17--l l3 ALFRED L. LEAVITT, Primary Examiner.

E. B. LIPSCOMB, Assistant Examiner. 

4. A PROCESS FOR TREATING PITCH IMPREGNATED FIBRE TUBES COMPRISING THE STEPS OF, IMMERSING A STACK OF FIBRE TUBES IN A BATH OF MOLTEN PITCH TO IMPREGNATE SAID TUBES WITH SAID PITCH, REMOVING SAID STACK OF IMPREGNATED TUBES FROM SAID BATH TO AN ELEVATED VERTICALLY EXTENDING POSITION OVER SAID BATH TO PERMIT EXCESS PITCH TO DRAIN FROM SAID TUBES INTO SAID BATH, ENCLOSING THE UPPER END PORTIONS OF SAID ELEVATED TUBES WITH A CHAMBER SUBSTANTIALLY CIRCULAR IN HORIZONTAL CROSS-SECTION WITH SAID TUBE END PORTIONS IN CLOSE FITTING RELATIONSHIP WITH SAID CHAMBER, ENCLOSING SAID CHAMBER AND SAID ELEVATED TUBES IN AN ENCLOSURE, INTRODUCING A FLOW OF COOLING AIR TANGENTIALLY INTO SAID CHAMBER WHEREBY SAID FLOW OF COOLING AIR FLOWS IN AN ARCUATE PATH DEFINED BY THE WALLS OF SAID CHAMBER AND IS SUBSEQUENTLY DIRECTED VERTICALLY DOWNWARD THROUGH THE INTERIORS AND OVER THE UPPER SURFACES OF SAID ELEVATED TUBES IN OPPOSITION TO THE HOT AIR CURRENTS NORMALY RISING FROM THE LOWER EXTREMITIES OF SAID TUBES TO QUICKLY AND UNIFORMLY CHILL THE PITCH COATING THROUGHOUT THE SURFACES OF SAID TUBES AND REMOVING FROM SAID ENCLOSURE THE AIR INTRODUCED INTO SAID CHAMBER. 